Is it normal to experience pain on your knee/s after or during a run? What are the possible treatment? Thanks

Yes. It would be best to reduce activities that aggrevate the pain and resume once healing has taken place. If pain persistent, would recommend evaluation by your doctor. Running is a great cardiovascular exercise, however, can increase risk of osteoarthritis in your knees and other lower extremity joints.
Depends. Its not uncommon at all. Treastment depends on what's causing the pain. See your doctor for a diagnosis.